Effluents containing organic and/or inorganic contaminants have to be purified for ecological and economic reasons. Such effluents are generated in various processes which employ naphthalenesulfonate-based condensates, e.g. as a dispersant in emulsion polymerizations.
U.S. Pat. No. 5,015,456 (Verbueken et al.) discloses a continuous process for the removal of at least one of nitrate and organic contaminants from an aqueous effluent. The process comprises subjecting said effluent to extractive liquid ion-exchange with a long-chain alkylamine dissolved in an organic solvent and present in the sulfate salt form, and reextracting the loaded organic phase with a base, the treated effluent being recycled for reuse. It is taught that in order to obtain an efficient concomitant extraction of the organic COD-components, even in the presence of considerably higher concentrations of inorganic sulfate ions, the amine extractant should be available in the sulfate form, as is also required for the removal of nitrate.